1. Field of the Invention
The present invention relates to novel compounds having retinoid-like biological activity. More specifically, the present invention relates to tricyclo[6.2.202,7]dodeca-2(7),3,5-trien-4-carbonyl)amino]-phenyl and tricyclo[6.2.202,7]dodeca-2(7),3,5-trien-4-carbonyl)amino]-heteroaryl and related compounds having RARxcex1 receptor selective biological activity.
2. Background Art
Compounds which have retinoid-like activity are well known in the art, and are described in numerous United States and other patents and in scientific publications. It is generally known and accepted in the art that retinoid-like activity is useful for treating animals of the mammalian species, including humans, for curing or alleviating the symptoms and conditions of numerous diseases and conditions. In other words, it is generally accepted in the art that pharmaceutical compositions having a retinoid-like compound or compounds as the active ingredient are useful as regulators of cell proliferation and differentiation, and particularly as agents for treating skin-related diseases, including, actinic keratoses, arsenic keratoses, inflammatory and non-inflammatory acne, psoriasis, ichthyoses and other keratinization and hyperproliferative disorders of the skin, eczema, atopic dermatitis, Darriers disease, lichen planus, prevention and reversal of glucocorticoid damage (steroid atrophy), as a topical anti-microbial, as skin anti-pigmentation agents and to treat and reverse the effects of age and photo damage to the skin. Retinoid compounds are also useful for the prevention and treatment of cancerous and precancerous conditions, including, premalignant and malignant hyperproliferative diseases such as cancers of the breast, skin, prostate, cervix, uterus, colon, bladder, esophagus, stomach, lung, larynx, oral cavity, blood and lymphatic system, metaplasias, dysplasias, neoplasias, leukoplakias and papillomas of the mucous membranes and in the treatment of Kaposi""s sarcoma. In addition, retinoid compounds can be used as agents to treat diseases of the eye, including, without limitation, proliferative vitreoretinopathy (PVR), retinal detachment, dry eye and other corneopathies, as well as in the treatment and prevention of various cardiovascular diseases, including, without limitation, diseases associated with lipid metabolism such as dyslipidemias, prevention of post-angioplasty restenosis and as an agent to increase the level of circulating tissue plasminogen activator (TPA). Other uses for retinoid compounds include the prevention and treatment of conditions and diseases associated with human papilloma virus (HPV), including warts and genital warts, various inflammatory diseases such as pulmonary fibrosis, ileitis, colitis and Krohn""s disease, neurodegenerative diseases such as Alzheimer""s disease, Parkinson""s disease and stroke, improper pituitary function, including insufficient production of growth hormone, modulation of apoptosis, including both the induction of apoptosis and inhibition of T-Cell activated apoptosis, restoration of hair growth, including combination therapies with the present compounds and other agents such as MinoxidilR, diseases associated with the immune system, including use of the present compounds as immunosuppressants and immunostimulants, modulation of organ transplant rejection and facilitation of wound healing, including modulation of chelosis. Retinoid compounds have relatively recently been also discovered to be useful for treating type II non-insulin dependent diabetes mellitus (NIDDM).
It is now general knowledge in the art that two main types of retinoid receptors exist in mammals (and other organisms). The two main types or families of receptors are respectively designated the RARs and RXRs. Within each type there are subtypes; in the RAR family the subtypes are designated RARxcex1, RARxcex2 and RARxcex3, in RXR the subtypes are: RXRxcex1, RXRxcex2 and RXRxcex3. It has also been established in the art that the distribution of the two main retinoid receptor types, and of the several sub-types is not uniform in the various tissues and organs of mammalian organisms. Moreover, it is generally accepted in the art that many unwanted side effects of retinoids are mediated by one or more of the RAR receptor subtypes. Accordingly, among compounds having agonist-like activity at retinoid receptors, specificity or selectivity for one of the main types or families, and even specificity or selectivity for one or more subtypes within a family of receptors, is considered a desirable pharmacological property. Some compounds bind to one or more RAR receptor subtypes, but do not trigger the response which is triggered by agonists of the same receptors. A compound that binds to a biological receptor but does not trigger an agonist-like response is usually termed an antagonist. Accordingly, the xe2x80x9ceffectxe2x80x9d of compounds on retinoid receptors may fall in the range of having no effect at all, (inactive compound, neither agonist nor antagonist) or the compound may elicit an agonist-like response on all receptor subtypes (pan-agonist). As still another alternative a compound may be a partial agonist and/or partial antagonist of certain receptor subtypes if the compound binds to but does not activate certain receptor subtype or subtypes but elicits an agonist-like response in other receptor subtype or subtypes.
Recently, a two-state model for certain receptors, including the above-mentioned retinoid receptors, have emerged. In this model, an equilibrium is postulated to exist between inactive receptors and spontaneously active receptors which are capable of coupling with a G protein in the absence of a ligand (agonist). In this model, so-called xe2x80x9cinverse agonistsxe2x80x9d shift the equilibrium toward inactive receptors, thus bringing about an overall inhibitory effect. Neutral antagonists do not effect the receptor equilibrium but are capable of competing for the receptors with both agonists (ligands) and with inverse agonists. U.S. Pat. No. 5,877,207 titled xe2x80x9cSynthesis and Use of Retinoid Compounds Having Negative Hormone and/or Antagonist Activitiesxe2x80x9d describes the foregoing two-state model and the use of retinoid antagonist and negative hormones in detail.
Among the scientific publications Dawson and William H. Okamura, Chemistry and Biology of Synthetic Retinoids, published by CRC Press Inc., 1990, pages 334-335, 354 and 324-356 is of special interest as an overview of the prior art on the subject.
The following is a list of United States and foreign patents and publications which disclose compounds having structural similarity to the compounds of the present invention, or disclose compounds having RARxcex1 selective agonist-like activity: U.S. Pat. Nos. 6,235,923; 6,245,786; 6,252,090; 6,342,602; 6,344,561; 6,387,950; 5,965,606; 6,037,488; 6,037,488; 6,187,950; 5,739,338; 5,760,276; 5,037,825; 5,420,145; 5,523,457; 5,559,248; 5,648,385; EPO 0 478 787; EPO 0 617 020; EPO 0 661 259; EPO 0 661 261; Eyrolles et al. J. Med. Chem. 1994 37 pp 1508-1517; Graupner et al. Biochem. Biophys. Res. Commun. 179 1991 pp 1554-1561; Kagechika et al. Biochem. Biophys. Res. Commun. 155 1988 pp 503-508; Kagechika et al. J. Med. Chem. 1988 31 pp 2182-2192; Standeven et al. Toxicology Letters 92 (1997) pp 231-240; Chem. Abstracts 117 (1992) 117:124091j; Teng et al. J. Med. Chem. 1997 40 pp 2445-2451; Teng et al. J. Med. Chem. 1996 39 pp 3035-3038; Nagpal et al. J. of Biol. Chem. 270 (1995) pp 923-927.
The present invention relates to compounds of Formula 1
where R1 is independently H, or alkyl of 1 to 6 carbons;
R2 is independently H, or alkyl of 1 to 6 carbons;
R3 is alkyl of 1 to 6 carbons, or halogen;
m is an integer having the values of 0 to 4;
R4 independently is alkyl of 1 to 6 carbons or halogen;
n is an integer having the values of 0 to 2;
R5 is H or OH;
Y is a phenyl or naphthyl group, or heteroaryl selected from a group consisting of pyridyl, thienyl, furyl, pyridazinyl, pyrimidinyl, pyrazinyl, thiazolyl, oxazolyl, imidazolyl and pyrrazolyl, said phenyl and heteroaryl groups being optionally substituted with one or two R6 groups;
R6 is halogen, alkyl of 1 to 10 carbons, fluoro substituted alkyl of 1 to 6 carbons, alkoxy of 1 to 10 carbons, or alkylthio of 1 to 10 carbons;
A is (CH2)q where q is 0-5, lower branched chain alkyl having 3-6 carbons, cycloalkyl having 3-6 carbons, alkenyl having 2-6 carbons and 1 or 2 double bonds, alkynyl having 2-6 carbons and 1 or 2 triple bonds;
B is COOH or a pharmaceutically acceptable salt thereof, COOR8, CONR9R10, xe2x80x94CH2l OH, CH2OR11, CH2OCOR11, CHO, CH(OR12)2, CHOR13O, xe2x80x94COR7, CR7(OR12)2, CR7OR13O, or tri-lower alkylsilyl, where R7 is an alkyl group of 1 to 6 carbons, cycloalkyl of 3 to 5 carbons, or alkenyl group containing 2 to 5 carbons, R8 is an alkyl group of 1 to 10 carbons or trimethylsilylalkyl where the alkyl group has 1 to 10 carbons, or a cycloalkyl group of 5 to 10 carbons, or CH2OCH3, or R8 is phenyl or C1-6 alkylphenyl, R9 and R10 independently are hydrogen, an alkyl group of 1 to 10 carbons, or a cycloalkyl group of 5-10 carbons, or phenyl or C1-6alkylphenyl, R11 is alkyl of 1 to 6 carbons, phenyl or C1-6alkylphenyl, R12 is alkyl of 1 to 6 carbons, and R13 is divalent alkyl radical of 2-5 carbons, or a pharmaceutically acceptable salt of said compound.
In a second aspect, this invention relates to the use of the compounds of Formula 1 for the treatment of skin-related diseases, including, without limitation, actinic keratoses, arsenic keratoses, inflammatory and non-inflammatory acne, psoriasis, ichthyoses and other keratinization and hyperproliferative disorders of the skin, eczema, atopic dermatitis, Darriers disease, lichen planus, prevention and reversal of glucocorticoid damage (steroid atrophy), as a topical anti-microbial, as skin anti-pigmentation agents and to treat and reverse the effects of age and photo damage to the skin. The compounds are also useful for the prevention and treatment of metabolic diseases such as type II diabetes and diabetes mellitus and for prevention and treatment of cancerous and precancerous conditions, including, premalignant and malignant hyperproliferative diseases such as cancers of the breast, skin, prostate, cervix, uterus, colon, bladder, esophagus, stomach, lung, larynx, oral cavity, blood and lymphatic system, metaplasias, dysplasias, neoplasias, leukoplakias and papillomas of the mucous membranes and in the treatment of Kaposi""s sarcoma. In addition, the present compounds can be used as agents to treat diseases of the eye, including, without limitation, proliferative vitreoretinopathy (PVR), retinal detachment, dry eye and other corneopathies, as well as in the treatment and prevention of various cardiovascular diseases, including, without limitation, diseases associated with lipid metabolism such as dyslipidemias, prevention of post-angioplasty restenosis and as an agent to increase the level of circulating tissue plasminogen activator (TPA). Other uses for the compounds of the present invention include the prevention and treatment of conditions and diseases associated with Human papilloma virus (HPV), including warts and genital warts, various inflammatory diseases such as pulmonary fibrosis, ileitis, colitis and Krohn""s disease, neurodegenerative diseases such as Alzheimer""s disease, Parkinson""s disease and stroke, improper pituitary function, including insufficient production of growth hormone, modulation of apoptosis, including both the induction of apoptosis and inhibition of T-Cell activated apoptosis, restoration of hair growth, including combination therapies with the present compounds and other agents such as MinoxidilR, diseases associated with the immune system, including use of the present compounds as immunosuppressants and immunostimulants, modulation of organ transplant rejection and facilitation of wound healing, including modulation of chelosis.
Generally speaking, the second aspect of the invention relates to the use of the novel compounds to prevent or treat diseases and conditions which are responsive to compounds that promote the expression of or bind to receptors belonging to the steroid or thyroid receptor superfamily.
This invention also relates to a pharmaceutical formulation comprising a compound of Formula 1 in admixture with a pharmaceutically acceptable excipient, said formulation being adapted for administration to a mammal , including a human being, to treat or alleviate the conditions which were described above as treatable by retinoids.
Assays of Retinoid-like Biological Activity
A classic measure of retinoic acid activity involves measuring the effects of retinoic acid on ornithine decarboxylase. The original work on the correlation between retinoic acid and a decrease in cell proliferation was done by Verma and Boutwell, Cancer Research, 1977, 37, 2196-2201. That reference discloses that ornithine decarboxylase (ODC) activity increased precedent to polyamine biosynthesis. It has been established elsewhere that increases in polyamine synthesis can be correlated or associated with cellular proliferation. Thus, if ODC activity could be inhibited, cell hyperproliferation could be modulated. Although all cases for ODC activity increases are unknown, it is known that 12-0-tetradecanoylphorbol-13-acetate (TPA) induces ODC activity. Retinoic acid inhibits this induction of ODC activity by TPA. An assay essentially following the procedure set out in Cancer Research: 1662-1670,1975 may be used to demonstrate inhibition of TPA induction of ODC by compounds of this invention. xe2x80x9cIC60xe2x80x9d is that concentration of the test compound which causes 60% inhibition in the ODC assay. By analogy, xe2x80x9cIC80xe2x80x9d, for example, is that concentration of the test compound which causes 80% inhibition in the ODC assay.
Other assays described below, measure the ability of the compounds of the present invention to bind to, and/or activate various retinoid receptor subtypes. When in these assays a compound binds to a given receptor subtype and activates the transcription of a reporter gene through that subtype, then the compound is considered an agonist of that receptor subtype. Conversely, a compound is considered an antagonist of a given receptor subtype if in the below described co-tranfection assays the compound does not cause significant transcriptional activation of the receptor regulated reporter gene, but nevertheless binds to the receptor with a Kd value of less than approximately 1 micromolar. In the below described assays the ability of the compounds to bind to RARxcex1, RARxcex2, RARxcex3, RXRxcex1, RXRxcex2 and RXRxcex3 receptors, and the ability or inability of the compounds to activate transcription of a reporter gene through these receptor subtypes can be tested. Because of the complex distribution of the different retinoid receptors in various organs of the mammalian body agonists of only one or two receptor subtypes may lend themselves to particularly useful therapeutic applications and may avoid serious side effects of conventional retinoid drugs.
As far as specific assays are concerned to demonstrate the activities of the compounds of the present invention, a chimeric receptor transactivation assay which tests for agonist-like activity in the RARxcex1, RARxcex2, RARxcex3, RXRxcex1 receptor subtypes, and which is based on work published by Feigner P. L. and Holm M (1989) Focus, 112 is described in detail in U.S. Pat. No. 5,455,265. The specification of U.S. Pat. No. 5,455,265 is hereby expressly incorporated by reference.
A holoreceptor transactivation assay and a ligand binding assay which measure the antagonist/agonist like activity of the compounds of the invention, or their ability to bind to the several retinoid receptor subtypes, respectively, are described in published PCT Application No. WO WO93/11755 (particularly on pages 30-33 and 37-41) published on Jun. 24, 1993, the specification of which is also incorporated herein by reference. A detailed experimental procedure for holoreceptor transactivations has been described by Heyman et al. Cell 68, 397-406, (1992); Allegretto et al. J. Biol. Chem. 268, 26625-26633, and Mangelsdorf et al. The Retinoids: Biology, Chemistry and Medicine, pp 319-349, Raven Press Ltd., New York, which are expressly incorporated herein by reference. The results obtained in this assay are expressed in EC50 numbers, as they are also in the chimeric receptor transactivation assay. The results of ligand binding assay are expressed in Kd numbers. (See Cheng et al. Biochemical Pharmacology Vol. 22 pp 3099-3108, expressly incorporated herein by reference.)
Still another transactivation assay, the xe2x80x9cPGR assayxe2x80x9d is described in the publication Klein et al. J. Biol. Chem. 271, 22692-22696 (1996) which is expressly incorporated herein by reference, and a detailed description is also provided below. The results of the PGR assay are also expressed in EC50 numbers (nanomolar concentration).
CV-1 cells (4xc3x97105 cells/well) were transiently transfected with the luciferase reporter plasmid MTV4(R5G)-Luc (0.7 ug/well) containing four copies of the R5G retinoid DNA response element along with the RXRxcex1 expression plasmid pRS-hRXRxcex1 (0.1 ug/well) and one of the RAR-P-GR expression plasmids (0.05 ug/well) in 12 well plates via calcium phosphate precipitation Chen et al. (1987) Mol. Cell. Biol. 7, 2745-2752 as described by Klein et al. in J. Biol. Chem. 271, 22692, referenced above. The three different RAR-P-GR expression plasmids, pRS-RARxcex1-P-GR, pcDNA3-RARxcex2-P-GR and pcDNA3-RARxcex3-P-GR, express RARxcex1, RARxcex2 and RARxcex3 receptors, respectively, which contain modified DNA binding domains such that their xe2x80x9cP-boxesxe2x80x9d have been altered to that of the glucocorticoid receptor. These RAR-P-GR receptors bind to DNA as heterodimeric complexes with RXR. Specifically, the RAR-P-GR receptors bind retinoic acid response elements designated R5G, comprised of two RAR half sites (nucleotide sequence 5xe2x80x2-GGTTCA-3xe2x80x2) separated by 5 base pairs in which the 3xe2x80x2-half site has been modified to that of a glucocorticoid receptor half site, 5xe2x80x2-AGAACA-3xe2x80x2. To allow for various in transfection efficiency a xcex2-galactosidase expression plasmid (0.01 ug/well) was used as an internal control. Alternatively, the assay was performed in a 96-well microtiter plate format (5000 cells/well) in a manner which was identical to that described above except ⅕ of the amount of the DNA-calcium phosphate precipitant (20 xcexcl instead of 100 xcexcl) was applied to each well. Eighteen hours after introduction of the DNA precipitants, cells were rinsed with phosphate buffered saline (PBS) and fed with D-MEM (Gibco-BRL) containing 10% activated charcoal extracted fetal bovine serum (Gemini Bio-Products). Cells were treated for 18 hours with the compounds indicated in the figures. After rinsing with PBS cells were lysed with luciferase activity was measured as previously described in de Wet (1987) Mol. Cell. Biol. 7, 725-737. Luciferase values represent the mean+SEM of triplicate determinations normalized to xcex2-galactosidase activity.
Table 1 discloses the activity of certain exemplary compounds of the invention in the above-described ligand binding assay. Table 1 also discloses three of the most preferred compounds of the invention, shown in their free carboxylic acid form. As it can be seen from Table 1, the compounds of the invention bind specifically or selectively to RARxcex1 retinoid receptors.
Modes of Administration
The compounds of this invention may be administered systemically or topically, depending on such considerations as the condition to be treated, need for site-specific treatment, quantity of drug to be administered, and numerous other considerations. Thus, in the treatment of dermatoses, it will generally be preferred to administer the drug topically, though in certain cases such as treatment of severe cystic acne or psoriasis, oral administration may also be used. Any common topical formulation such as a solution, suspension, gel, ointment, or salve and the like may be used. Preparation of such topical formulations are well described in the art of pharmaceutical formulations as exemplified, for example, by Remington""s Pharmaceutical Science, Edition 17, Mack Publishing Company, Easton, Pa. For topical application, these compounds could also be administered as a powder or spray, particularly in aerosol form. If the drug is to be administered systemically, it may be confected as a powder, pill, tablet or the like or as a syrup or elixir suitable for oral administration. For intravenous or intraperitoneal administration, the compound will be prepared as a solution or suspension capable of being administered by injection. In certain cases, it may be useful to formulate these compounds by injection. In certain cases, it may be useful to formulate these compounds in suppository form or as extended release formulation for deposit under the skin or intramuscular injection.
Other medicaments can be added to such topical formulation for such secondary purposes as treating skin dryness; providing protection against light; other medications for treating dermatoses; medicaments for preventing infection, reducing irritation, inflammation and the like.
Treatment of dermatoses or any other indications known or discovered to be susceptible to treatment by retinoic acid-like compounds will be effected by administration of the therapeutically effective dose of one or more compounds of the instant invention. A therapeutic concentration will be that concentration which effects reduction of the particular condition, or retards its expansion. In certain instances, the compound potentially may be used in prophylactic manner to prevent onset of a particular condition.
A useful therapeutic or prophylactic concentration will vary from condition to condition and in certain instances may vary with the severity of the condition being treated and the patient""s susceptibility to treatment. Accordingly, no single concentration will be uniformly useful, but will require modification depending on the particularities of the disease being treated. Such concentrations can be arrived at through routine experimentation. However, it is anticipated that in the treatment of, for example, acne, or similar dermatoses, that a formulation containing between 0.01 and 1.0 milligrams per milliliter of formulation will constitute a therapeutically effective concentration for total application. If administered systemically, an amount between 0.01 and 5 mg per kg of body weight per day would be expected to effect a therapeutic result in the treatment of many diseases for which these compounds are useful.
Definitions
The term alkyl refers to and covers any and all groups which are known as normal alkyl, branched-chain alkyl, cycloalkyl and also cycloalkyl-alkyl. The term alkenyl refers to and covers normal alkenyl, branch chain alkenyl and cycloalkenyl groups having one or more sites of unsaturation. Similarly, the term alkynyl refers to and covers normal alkynyl, and branch chain alkynyl groups having one or more triple bonds.
Unless specified otherwise, lower alkyl means the above-defined broad definition of alkyl groups having 1 to 6 carbons in case of normal lower alkyl, and as applicable 3 to 6 carbons for lower branch chained and cycloalkyl groups. Lower alkenyl is defined similarly having 2 to 6 carbons for normal lower alkenyl groups, and 3 to 6 carbons for branch chained and cyclo-lower alkenyl groups. Lower alkynyl is also defined similarly, having 2 to 6 carbons for normal lower alkynyl groups, and 4 to 6 carbons for branch chained lower alkynyl groups.
The term xe2x80x9cesterxe2x80x9d as used here refers to and covers any compound falling within the definition of that term as classically used in organic chemistry. It includes organic and inorganic esters. Where B of Formula 1 is xe2x80x94COOH, this term covers the products derived from treatment of this function with alcohols or thiols preferably with aliphatic alcohols having 1-6 carbons. Where the ester is derived from compounds where B is xe2x80x94CH2OH; this term covers compounds derived from organic acids capable of forming esters including phosphorous based and sulfur based acids, or compounds of the formula xe2x80x94CH2OCOR11 where R11 is a variable as defined above in connection with Formula 1.
Unless stated otherwise in this application, preferred esters are derived from the saturated aliphatic alcohols or acids of ten or fewer carbon atoms or the cyclic or saturated aliphatic cyclic alcohols and acids of 5 to 10 carbon atoms. Particularly preferred aliphatic esters are those derived from lower alkyl acids and alcohols. Also preferred are the phenyl or lower alkyl phenyl esters.
The term amide has the meaning classically accorded that term in organic chemistry. In this instance it includes the unsubstituted amides and all aliphatic and aromatic mono- and di-substituted amides. Unless stated otherwise in this application, preferred amides are the mono- and di-substituted amides derived from the saturated aliphatic radicals of ten or fewer carbon atoms or the cyclic or saturated aliphatic-cyclic radicals of 5 to 10 carbon atoms. Particularly preferred amides are those derived from substituted and unsubstituted lower alkyl amines. Also preferred are mono-and disubstituted amides derived from the substituted and unsubstituted phenyl or lower alkylphenyl amines. Unsubstituted amides are also preferred.
Acetals and ketals include the radicals of the formula xe2x80x94CK where K is (xe2x80x94OR)2. Here, R is lower alkyl. Also, K may be xe2x80x94OR7Oxe2x80x94 where R7 is lower alkyl of 2-5 carbon atoms, straight chain or branched.
A pharmaceutically acceptable salt may be prepared for any compound in this invention having a functionality capable of forming a salt, for example an acid functionality. A pharmaceutically acceptable salt is any salt which retains the activity of the parent compound and does not impart any deleterious or untoward effect on the subject to which it is administered and in the context in which it is administered.
Pharmaceutically acceptable salts may be derived from organic or inorganic bases. The salt may be a mono or polyvalent ion. Of particular interest are the inorganic ions, sodium, potassium, calcium, and magnesium. Organic salts may be made with amines, particularly ammonium salts such as mono-, di- and trialkyl amines or ethanol amines. Salts may also be formed with caffeine, tromethamine and similar molecules. Where there is a nitrogen sufficiently basic as to be capable of forming acid addition salts, such may be formed with any inorganic or organic acids or alkylating agent such as methyl iodide. Preferred salts are those formed with inorganic acids such as hydrochloric acid, sulfiric acid or phosphoric acid. Any of a number of simple organic acids such as mono-, di- or tri-acid may also be used.
The compounds of the present invention are capable of existing as trans and cis (E and Z) isomers relative to olephinic double bonds, cycloalkyl rings provided one or more olephinic bonds and/or one or more cycloalkyl ring is present in the compound. The invention covers trans as well as cis isomers relative to each center that gives rise to such isomerism, as well as mixture of such isomers. The compounds of the present invention may and typically do contain one or more chiral centers and therefore may exist in enantiomeric and diastereomeric forms. The scope of the present invention is intended to cover all isomers per se, as well as mixtures of cis and trans isomers, mixtures of diastereomers and racemic mixtures of enantiomers (optical isomers) as well.
Generally speaking the compounds of the invention can be obtained by the reactions illustrated in Reaction Scheme 1. The starting material in this scheme is a cyclohexane derivative of Formula 2, which already has the R1, R2 and R3 substituents, where the variables R1, R2 and R3 are defined as in connection with Formula 1. Such substituted cyclohexane derivatives can be obtained in accordance with the chemical scientific and/or patent literature, or in accordance with such modification of the scientific and/or patent literature which is readily apparent to those skilled in the art. An example of a compound of Formula 2 is 1,4 dimethylcyclohexane which is used as a starting material in the synthesis of several preferred compounds of the invention. 1,4-Dimethylcyclohexane is available from Aldrich Chemical Company, Inc (Aldrich). The cyclohexane derivative of Formula 2 is reacted with tertiary-butyl chloride in the presence of aluminum chloride (AlCl3) to provide the 2,4-dichlorinated cyclohexane derivative of Formula 3. The 2,4-dichlorinated cyclohexane derivative of Formula 3 is then reacted with a benzene derivative of Formula 4 in the presence of aluminum chloride. Although Reaction Scheme 1 illustrates the synthesis of compounds of the invention where the group corresponding to the R5 group of Formula 1 is OH (a phenol derivative) it will be readily apparent to those skilled in the art that the synthesis of such compounds of the invention where the variable R5 represents hydrogen can also be performed in accordance with scheme with only such modification of the scheme which will become readily apparent to those skilled in the art. 
The product of this Friedel Crafts type reaction is a spiro compound of Formula 5, which is then brominated to provide a bromo derivative Spiro compound of Formula 6. The phenolic hydroxyl group of the bromo spiro compound of Formula 6 is protected with a methyl group as a result of reaction with methyl iodide in the presence of base, such as potassium carbonate, to yield the bromo-methoxy Spiro compound of Formula 7. The bromo-methoxy spiro compound of Formula 7 is then reacted with strong base, such as normal butyl lithium, and carbon dioxide, to xe2x80x9ccapturexe2x80x9d carbon dioxide and provide the Spiro carboxylic acid derivative of Formula 8. The spiro carboxylic acid derivative of Formula 8 is first reacted with thionyl chloride to provide the corresponding acid chloride, and thereafter with an amino-aryl- or amino-heteroaryl compound of Formula 9 in a basic solvent, such as pyridine. Examples of reagents of Formula 9 are ethyl 4-aminobenzoate, ethyl 4-amino-2-fluorobenzoate, ethyl-4-amino-2,4-difluorobenzoate, ethyl 2-amino-pyridine-5-carboxylate, ethyl 2-amino-pyridine-4-carboxylate, ethyl 2-amino thiophene-4-carboxylate, ethyl 2-amino thiophene-5-carboxylate, ethyl 2-amino furan-4-carboxylate and ethyl 2-amino furan-5-carboxylate. Ethyl 4-aminobenzoate is available from Aldrich, ethyl 4-amino-2-fluorobenzoate and ethyl-4-amino-2,4-difluorobenzoate can be obtained in accordance with the synthetic procedures described in U.S. Pat. No. 5,663,357, incorporated herein by reference. Generally speaking, the compounds of Formula 9 can be obtained in accordance with the chemical scientific and/or patent literature, or in accordance with such modification of the scientific and/or patent literature which is readily apparent to those skilled in the art.
The reaction of the carboxylic acid chloride made from the spiro carboxylic acid derivative of Formula 8 with the amino-aryl- or amino-heteroaryl compound of Formula 9 yields the spiro amide compound of Formula 10. The methyl protecting group from the phenolic hydroxyl of the compound of Formula 10 is then removed by treatment of boron triboromide (BBr3) in an anhydrous aprotic solvent, such as methylene dichloride. The resulting spiro-amide compound of Formula 11 is a compound of the invention, within the scope of Formula 1. The compound of Formula 11 can be converted into further compounds of the invention within the scope of Formula 1 by such reactions as esterification, saponification, homologation, reduction to aldehyde or alcohol stage and the like, which per se are well known in the art. These reactions usually involve transformations of the group B in Formula 1 but are not necessarily limited to those. For some of the compounds of the invention these transformations are preferably performed on the intermediate of Formula 10, rather than on the compound of Formula 11. Some of the known and published general principles and synthetic methodology employed in the transformations of the B group are briefly described below.
Carboxylic acids are typically esterified by refluxing the acid in a solution of the appropriate alcohol in the presence of an acid catalyst such as hydrogen chloride or thionyl chloride. Alternatively, the carboxylic acid can be condensed with the appropriate alcohol in the presence of dicyclohexylcarbodiimide (DCC) and 4-(dimethylamino)pyridine (MAP). The ester is recovered and purified by conventional means. Acetals and ketals are readily made by the method described in March, xe2x80x9cAdvanced Organic Chemistry,xe2x80x9d 2nd Edition, McGraw-Hill Book Company, p 810). Alcohols, aldehydes and ketones all may be protected by forming respectively, ethers and esters, acetals or ketals by known methods such as those described in McOmie, Plenum Publishing Press, 1973 and Protecting Groups, Ed. Greene, John Wiley and Sons, 1981.
The acids and salts derived from compounds of the invention are readily obtainable from the corresponding esters. Basic saponification with an alkali metal base will provide the acid. For example, an ester of the invention may be dissolved in a polar solvent such as an alkanol, preferably under an inert atmosphere at room temperature, with about a three molar excess of base, for example, lithium hydroxide or potassium hydroxide. The solution is stirred for an extended period of time, between 15 and 20 hours, cooled, acidified and the hydrolysate recovered by conventional means.
The amide may be formed by any appropriate amidation means known in the art from the corresponding esters or carboxylic acids. One way to prepare such compounds is to convert an acid to an acid chloride and then treat that compound with ammonium hydroxide or an appropriate amine. For example, the ester is treated with an alcoholic base solution such as ethanolic KOH (in approximately a 10% molar excess) at room temperature for about 30 minutes. The solvent is removed and the residue taken up in an organic solvent such as diethyl ether, treated with a dialkyl formamide and then a 10-fold excess of oxalyl chloride. This is all effected at a moderately reduced temperature between about xe2x88x9210 degrees and +10 degrees C. The last mentioned solution is then stirred at the reduced temperature for 14 hours, preferably 2 hours. Solvent removal provides a residue which is taken up in an inert organic solvent such as benzene, cooled to about 0 degrees C. and treated with concentrated ammonium hydroxide. The resulting mixture is stirred at a reduced temperature for 1-4 hours. The product is recovered by conventional means.
Alcohols are made by converting the corresponding acids to the acid chloride with thionyl chloride or other means (J. March, xe2x80x9cAdvanced Organic Chemistryxe2x80x9d, 2nd Edition, McGraw-Hill Book Company), then reducing the acid chloride with sodium borohydride (March, ibid, pg. 1124), which gives the corresponding alcohols. Alternatively, esters may be reduced with lithium aluminum hydride at reduced temperatures. Alkylating these alcohols with appropriate alkyl halides under Williamson reaction conditions (March, ibid, pg. 357) gives the corresponding ethers. These alcohols can be converted to esters by reacting them with appropriate acids in the presence of acid catalysts or dicyclohexylcarbodiimide and dimethylaminopyridine.
Aldehydes can be prepared from the corresponding primary alcohols using mild oxidizing agents such as pyridinium dichromate in methylene chloride (Corey, E. J., Schmidt, G., Tet. Lett., 399, 1979), or dimethyl sulfoxide/oxalyl chloride in methylene chloride (Omura, K., Swern, D., Tetrahedron, 1978, 34, 1651).
Acetals or ketals can be prepared from the corresponding aldehyde or ketone by the method described in March, ibid, p 810.
With reference to the symbol Y in Formula 1 the preferred compounds of the invention are those where Y is phenyl. Compounds are also preferred where Y is a bivalent naphthyl, pyridyl, thienyl or furyl radical. When Y is phenyl, the compounds are generally preferred with the phenyl radical being 1,4 (para) substituted with the carbamoyl (amide) and Axe2x80x94B groups. When Y is pyridyl, the compounds are generally preferred with the pyridyl group being 2,5 substituted with the carbamoyl (amide) and Axe2x80x94B groups. When Y is phenyl, compounds are also preferred with an R6 substituent in the ortho, and/or ortho and orthoxe2x80x2 positions relative to the Axe2x80x94B group.
The R1 group in the preferred compounds of the invention is H or alkyl of 1 to 3 carbons. Even more preferably R1 is methyl. R2 is preferably H or lower alkyl 1 to 3 carbons, and even more preferably R2 is hydrogen.
The non-aromatic portion of the condensed spiro moiety of the compounds of the invention is preferably not substituted with an R3 group, that is the variable m is preferably zero (0).
The aromatic portion of the condensed spiro moiety of the compounds of the invention is preferably not substituted with an R4 group, that is the variable n is preferably zero (0). Alternatively and just as preferably, n is one (1), the R4 group is halogen, preferably bromine, and the R4 group is in the 6-position of the condensed Spiro moiety. The numbering of the condensed Spiro moiety is indicated in Formula 1.
The variable R5 is H or OH, preferably OH. In some preferred compounds of the invention there is no optional variable R6, that is the aryl or heteroaryl ring is not substituted with an R6 group. In other preferred compounds of the invention the R6 group is preferably halogen, alkyl of 1 to 3 carbons, fluoro substituted alkyl of 1 to 3 carbons, alkoxy of 1 to 3 carbons, or alkylthio of 1 to 3 carbons. Among the halogens, the fluoro (F) substituent is preferred.
The presently most preferred compounds of the invention are shown as free carboxylic acids in Table 2, with reference to Formula 12, however it should be kept in mind that pharmaceutically acceptable salts and C1-6 alkyl esters, particularly ethyl and methyl esters of these compounds are also preferred. 